Tetrakisazo dyestuffs



United States Patent TETRAKISAZO DYESTUFFS Fritz Suckfiill, Leverkusen-Wiesdorf, Germany, assignor to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Application April 9, 1952, Serial No. 281,463

Claims priority, application Germany April 30, 1951 4 Claims. (Cl. 260-467) S0311 S0311 NH.COCH3 2 In this formula X stands for hydrogen or methyl.

The new tetrakisazo dyestuffs are obtainable by coupling a diazotized aminoazo-benzene disulfonic acid or a homologue thereof with 1-amino-3-acetylamino-benzene or l-arnino-3-acetylamino-6-methyl-benzene and converting the disazo dyestuffs thus obtained into the corresponding ureas in known manner. This can be done by condensing the amino-disazo dyestuffs with phosgene.

The new tetrakisazo dyestuffs dye cotton and fibers of regenerated cellulose red-orange shades fast to acid. Tetrakisazo dyestuffs of similar constitution are known from German Patent 223,753; in this patent, however, there are no dyestuffs mentioned containing 1-amino-3- acetylamino-benzene or its homologue as coupling component. The new dyestuffs excel these known dyestuffs in their good fastness to acids.

Example 1 35.7 parts of 4-aminoazo-benzene-3.4-disulfonic acid are diazotized with 6.9 parts of sodium nitrite at 5 C. parts of l-amino-3-acetylamino-benzene are added to the diazo compound. Coupling is completed by adding sodium acetate, and the dyestutf is isolated. After dissolving again, the dyestufl is treated with phosgene at 40 C. until a test portion shows that the reaction is complete.

After being isolated and dried, the dyestutf represents a dark powder which easily dissolves in water. When dyed on cotton, red-orange shades are obtained having a good fastness to brightening.

The new tetrakisazo dyestutf corresponds in the form of the free acid to the following formula:

2,708,668 Patented May 17, 1955 "ice Example 3 17.3 parts of l-arninobenzene-4-sulfonic acid are diazotized with 6.9 parts of sodium nitrite at 10 C., and the diazo compound is coupled in acetic medium with 18.7 parts of 1-amino-3-methylbenzene-6-sulfonic acid. The isolated monoazo dyestuif is further diazotized with 6.9 parts of sodium nitrite at 5 C., and the diazoazo compound is coupled in acetic medium with 15 parts of 1-amino-3-acetylaminobenzene. The aminodisazo dyestuff is, as described in Example I, converted into the symmetric urea, isolated and dried.

The dyestuif represents a dark powder and is easily soluble in water. It dyes cotton reddish orange shades with a good fastness to brightening. The dyestuff corresponds in the form of the free acid to the formula:

SOaH NH.C 0 CH3 2 I claim: 1. Tetrakisazo dyestuffs corresponding as free acids to the general formula:

S0311 S0311 NELCOCH; 2

in which X stands for one of the group consisting of hydrogen and methyl, dyeing cotton and fibers of regenerated cellulose red-orange shades fast to acid.

2. The tetrakisazo dyestuff corresponding as free acid to the formula:

SOaH NH.COCH: I

dyeing cotton and fibers of regenerated cellulose redorange shades.

3. The tetrakisazo dyestutr corresponding as free acid to the formula:

SOaH NHLC O CH: 2

dyeing cotton and fibers of regenerated cellulose redorange shades.

4. The tetrakisazo dyestulf corresponding as free acid to the formula:

dyeing cotton and fibers of regenerated cellulose reddish orange shades.

(EH: H

SOaH NH.COCH: 2 

1. TETRAKISAZO DYESTUFFS CORRESPONDING AS FREE ACIDS TO THE GENERAL FORMULA; 